CSVGuide
Converting CSV to JSON XML YAML and Excel in Practice
Convert one awkward CSV to JSON, JSON Lines, XML, YAML, Excel, Parquet, Markdown and SQL, read each back and see the cost on 193,708 rows.
22 min read
Topic
CSV
The format everyone exports and nobody specifies. Delimiters, quoting, encodings and loading it into a database intact.
CSV
Automating a Nightly CSV Export With cron and psql
A cron export that cannot publish a half-written file: lock, temporary name, row-count check, atomic rename. Real cron failed first, on the environment.
10 min read
CSV
Exporting CSV From the Database Straight to a Gzip File
Pipe a PostgreSQL export into gzip or zstd: 130 MB became 42 MB in 4.6 s, with six settings compared and the pipeline that exits 0 after a failed export.
8 min read
CSV
Writing Dates and Booleans to CSV That Others Can Read
One timestamp exported as 09:30+00, 16:30+07 and 04:30-05, and dd.mm.yyyy that pandas read as 3 January. Fix dates and booleans in the query, not the session.
9 min read
CSV
Exporting Large Tables to CSV Without Running Out of Memory
Export a 2,000,000 row table to CSV six ways: peak memory ranged from 11 MB to 2 GB, time from 1.6 s to 14 s. fetchall and pandas are the ones that run out.
9 min read
CSV
Exporting a CSV With Headers From SQLite on the Command Line
Export SQLite to CSV with a header row from the sqlite3 shell: CRLF endings by default, NULL against empty string, types and 2,000,000 rows in 3.5 s.
10 min read
CSV
Exporting a MongoDB Collection to CSV With mongoexport
mongoexport writes CSV only if you name the fields. See arrays, ObjectIds, nulls, the empty file and exit 0 on a typo, and 500,000 documents in 2.7 s.
10 min read
CSV
Exporting an Oracle Query to CSV With SQLcl From the Shell
Export an Oracle query to a quoted CSV with SQLcl: set the CSV format, spool to a file, fix date and number formats, and run it from a shell script.
8 min read
CSV
Exporting SQL Server Results to CSV With bcp and sqlcmd
How to export a SQL Server query to a real CSV with bcp: add the header row, quote fields yourself, fix dates and NULLs, and pick the right encoding.
10 min read
JSON
JSON Lines Versus CSV for Event Data and Log Exports
JSON Lines or CSV for event exports? Measured file size, compressed size and read time on 200,000 events, plus nesting, sparse fields and null handling.
6 min read
CSV
Exporting MySQL Query Results to CSV With INTO OUTFILE
INTO OUTFILE writes on the server and its popular recipe corrupts newlines and NULLs: 4 of 8 rows read back. A variant reads 7, a client script reads 8.
11 min read
CSV
Exporting a PostgreSQL Query to CSV With psql and COPY
Export a PostgreSQL query to CSV with psql: NULL against empty string, delimiter and quoting options, encodings, why variables fail and the file left behind.
9 min read
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